Extreme Cold Warning 2, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
410 AM AKST Sun Dec 29 2024

.SYNOPSIS...
The coming week will be all big bubble, and no trouble as high
pressure will continue to build over the state. This will bring
cold and dry conditions. The Western Interior as well as the North
Slope are already feeling the effects of the high pressure with
clear skies and temperatures in the 30s and 40s below zero. The
Eastern Interior valleys has some pesky stratus that is helping to
moderate temperatures. This stratus will dissipate by 9 AM today,
and when it does dissipate expect temperatures to rapidly drop.
This batch of cold air will persist through Monday.

&&

.DISCUSSION...
Key Weather Messages...

Central and Eastern Interior...
- Temperatures will begin to drop rapidly today as an arctic front
  brings 850 mb temperatures of around -16C. This will drop
  surface temperatures into the 20s and 30s below. The Yukon Flats
  could see temperatures approaching 40 below Monday night. As we
  go through the week expect temperatures to remain chilly and
  below normal.

- The higher elevation will see northeasterly winds of 25 to 35
  mph develop by noon today. These winds will last through
  Tuesday night. Along the Highway Summits there will likely be
  blowing snow, with the strongest gusts we could see visibilities
  reduced to 1/2 mile.

- With breezy conditions in the Interior, wind chills are a
  concern. Sunday night and Monday night will be the biggest
  nights of concern. The Yukon Flats and west towards Tanana
  could see wind chills approaching 55 below.

- A Tanana Valley Jet with gusts near 20 mph will begin to develop
  Monday afternoon. This would help to keep the area a bit
  milder.

West Coast and Western Interior...
- Temperatures will remain in the 20s and 30s below in the Western
  Interior Valleys through Tuesday night. We will see a warming
  trend in the Western Interior Valleys through the week. Coastal
  communities and communities in the Y-K Delta could see some
  cooler temperatures by the end of the week, with lows
  approaching 0.

- Northeasterly winds will persist through Tuesday afternoon, with
  the peak winds starting around 3PM today.Unalakleet to St.
  Lawrence Island could see gusts up to 45 mph.

North Slope and Brooks range...
- Temperatures this morning in the Arctic Plains have already
  reached the 30s and 40s below. The cold spot overnight was
  Umiat with a temperature of 44 below. The coastal communities
  are in the 20s below. Through the week the coastal communities
  will slowly warm up to the 10s below, while the Arctic Plains
  remain in the 30s below.

- Wind chills are approaching 60 below across the Arctic Plains
  and the Beaufort Sea Coastline tonight. These hazardous wind
  chills will continue Sunday night as easterly winds of 20 mph
  develop along the Arctic Coastline.

- Wind gusts from the east to 45 mph in Point Lay will result in
  blowing snow, and near blizzard conditions Sunday night through
  Tuesday morning.

Analysis and Forecast Confidence... There is pretty good
confidence until around Thursday. A 547 decameter high pressure
will remain over the Interior portion of the state. Both the ECMWF
and GFS are signaling that this high pressure has around a 2
sigma anomaly, which would put it into the 95th percentile of
high pressures for this date. The slight deviation between the
models in the short term is how long the coldest temperatures stay
around. The ECMWF, EC Ensemble, and GFS Ensemble want to warm the
Eastern Interior much faster bringing the temperatures to around
normal. The GFS deterministic however, brings in more reinforcing
cold air thats over the Yukon Territories in Canada. This would
keep the Eastern Interior in the 20s and 30s below through the
week.

Models begin to diverge on Thursday with the breakdown of the
omega block pattern. The GFS and Canadian want to split the high
pressure in two and bring cold air down into the Y-K Delta. While
the ECMWF builds a low pressure over the Canadian Archipelago, and
as it moves southwest it pushes the high pressure towards Far
Eastern Russia. The ECMWF has support from both the GFS Ensemble
and the ECMWF Ensemble. This pattern breakdown will bring in the
chance to see some more impactful weather by the end of next
weekend.

Extended Forecast Days 4-7... High pressure will remain over much
of the Interior through the week. Model guidance is showing a low
pressure breaking down the high by Friday and splitting it with
on location over Far Eastern Russia and the other in the Gulf of
Alaska. This low would move southwest from Northwest Canada to the
Y-K Delta. We would see some reinforcement of colder air as it
moves across the interior. However, the models are not agreeing on
the location of that low, or if it would split the high pressure
in two or just push the high to the northwest. This would effect
the strength of the cold air that get pushed into the interior.

Looking towards next weekend there could be a potential low
develop in the Gulf of Alaska, and could bring precip into our
forecast area by Sunday. The GFS solution for this would drape the
front across the Alaska Range and into the Eastern Interior. This
solution could bring some snowfall into the Interior, but it
would have to contend with a lot of dry air that would be in the
Interior. Meanwhile, the ECMWF would move the front into the Y-K
Delta bringing precipitation to the Y-K Delta and Seward
Peninsula.

Both solutions could bring impacts to our forecast area, but it
is still to far out and not enough certainty on making forecast
decisions on this. There has been day to day consistency that the
models have identified this feature. The solutions however have
not been consistent. We will continue to monitor this feature as
we go through the week.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...Winter Storm Watch for AKZ801.
PK...Gale Warning for PKZ801-804-850.
     Gale Warning for PKZ802.
     Brisk Wind Advisory for PKZ803-805-806.
     Brisk Wind Advisory for PKZ807.
     Brisk Wind Advisory for PKZ808-809-855-858.
     Brisk Wind Advisory for PKZ811-856.
     Brisk Wind Advisory for PKZ812.
     Gale Warning for PKZ816-851-854.
     Gale Warning for PKZ817.
     Heavy Freezing Spray Warning for PKZ851.
     Gale Warning for PKZ852-853.
     Brisk Wind Advisory for PKZ857.
&&